artifact:jar:dpml/transit/dpml-transit-main#2.1.1
Transit provides a flexible framework for dynamically retrieving system and application resources, constructing classloaders and management of plugins via an abstract resource identifier referred to as an artifact. As a resource management system Transit provides the foundation for building repository-enabled applications.
One of the more difficult tasks when building Java applications is classloader management. Often, when combining various projects together into an enterprise application, the application is not able to load the right classes at the right time, causing the application to fail in mysterious and sometimes subtle ways. Although a fundamental issue, classloading has remained a rather obscure topic. When combined with component-based development the classloader management concern can become a major configuration management concern. Transit provides a solution to this problem.
At the core of Transit is a URL protocol handler and a framework for custom content handlers. Content handlers provided by DPML include a deployment system that encapsulates a classloader defintion and deployment strategy, together with a handler supporting the establishment of a Java runtime process. Based on these, Transit is able to manage classloaders, not only effectively and nearly invisible to the casual user, but in a location independent way. That means, applications don't need to be concerned over where the jars and other resources are located, whether on the local file system, on LAN servers or somewhere on the Internet. This allows an application to provide extendability, hot-redeployment and more advanced services.